Use

The Coagulation Factor IX Activity Assay is useful for diagnosing deficiencies, particularly hemophilia B (Christmas disease). It is also used for assessing the impact of liver disease on hemostasis and investigating prolonged activated partial thromboplastin time. Factor IX is a vitamin K-dependent serine protease that is synthesized in the liver and participates in the intrinsic coagulation pathway. Congenital deficiency of factor IX presents as an X-linked recessive bleeding disorder (hemophilia B), characterized by symptoms such as hemarthroses, deep tissue bleeding, excessive bleeding with trauma, and ecchymoses. Acquired deficiency is commonly associated with liver disease, vitamin K deficiency, warfarin therapy, and rarely, inhibitors.